This invention relates generally to methods for bonding and systems thereof and, more particularly, to a method for electrostatic force bonding of at least one component to an assembly and a resulting system thereof.
The assembly of many Micro-Electro-Mechanical System (MEMS) structures requires the accurate placement of components or sub-components on a substrate. This is especially true for optical MEMS devices. Typically, the sub-components are placed at the desired location on the substrate and then are permanently bonded by using some form of adhesive or by actuation of MEMS locking structures.
Unfortunately, it is very difficult to maintain proper component or sub-component registration while undergoing the permanent bonding process. Sub-components or components may move out of alignment as the epoxies cure or as solder reflows due to forces that exceed the temporary holding mechanisms or techniques.
A method for electrostatic bonding in accordance with one embodiment of the present invention includes placing a first region of a first unit at least adjacent to a first region of a second unit. The first region of the first unit has trapped charge. A bond between the first region of the first unit and the first region of the second unit is formed by the electrostatic forces between the trapped charge and induced charge in the first region of the second unit.
A system for electrostatic bonding in accordance with another embodiment of the present invention includes a first unit having a first region with trapped charge and a second unit with a first region with induced charge. Electrostatic forces between the trapped charge in the first region of the first unit and the induced charge in the first region of the second unit bond the first and second units together.
A method for making first and second units for electrostatic bonding in accordance with another embodiment of the present invention includes depositing a first insulating layer on at least a portion of a first substrate of a first unit. A second insulating layer is deposited on at least a portion of the first insulating layer to form a dual dielectric. Trapped charge is established at an interface between the first and second insulating layers. A first substrate for the second unit is provided. The second insulating layer is bonded to the second substrate with electrostatic forces between the trapped charge and induced charge in the first substrate of the second unit.
A system for electrostatic bonding in accordance with another embodiment of the present invention includes a first substrate, a first insulating layer on at least a portion of the substrate, a second insulating layer on at least a portion of the first insulating layer, and a second substrate. An interface between the first and second insulating layers has trapped charge. The second substrate has induced charge and is bonded to the second insulating layer with electrostatic forces between the trapped charge and the induced charge.
A method for making first and second units for electrostatic bonding in accordance with another embodiment of the present invention includes depositing a first conductive layer on at least a portion of a first substrate for the first unit. A first insulating layer is deposited on at least a portion of the first conductive layer. A second insulating layer is deposited on at least a portion of the first insulating layer to form a dual dielectric. A second conductive layer is deposited on at least a portion of the second insulating layer. An electrical bias is applied between the first conductive layer and the second conductive layer to inject at least a portion of the trapped charge into the second insulating layer. At least a portion of the injected trapped charge becomes trapped at an interface between the first and second insulating layers. The second conductive layer is removed after the applying of the electrical bias. A first substrate for the second unit is provided. The third insulating layer is bonded to the second substrate with electrostatic forces between the trapped charge and induced charge in the first substrate of the second unit.
A system for electrostatic bonding in accordance with another embodiment of the present invention includes a first substrate, a first conductive layer on at least a portion of the substrate, a first insulating layer on at least a portion of the first conductive layer, a second insulating layer and a second substrate. The second insulating layer is on at least a portion of the first insulating layer to form a dual dielectric and has trapped charge residing at an interface between the first and second insulating layers. The second substrate is bonded to the third insulating layer with electrostatic forces between the trapped charge and induced charge in the second substrate.
A method for making first and second units for electrostatic bonding in accordance with another embodiment of the present invention includes depositing a first insulating layer on at least a portion of a first substrate for the first unit. A first conductive layer is deposited on at least a portion of the first insulating layer. A second insulating layer is deposited on at least a portion of the first conductive layer. Trapped charge is established in the first conductive layer. A first substrate for the second unit is provided. The second insulating layer is bonded to the first substrate for the second unit with electrostatic forces between the trapped charge and induced charge in the first substrate of the second unit.
A system for electrostatic bonding in accordance with another embodiment of the present invention includes a first substrate, a first insulating layer on at least a portion of the substrate, a first conductive layer on at least a portion of the first insulating layer, and a second insulating layer on at least a portion of the first conductive layer that has trapped charge. A second substrate is provided and is bonded to the second insulating layer with electrostatic forces between the trapped charge and induced charge in the second substrate.
A method for making first and second units for electrostatic bonding in accordance with another embodiment of the present invention includes depositing a first conductive layer on at least a portion of a first substrate for the first unit. A first insulating layer is deposited on at least a portion of the first conductive layer. A second conductive layer is deposited on at least a portion of the first insulating layer. A second insulating layer is deposited on at least a portion of the second conductive layer. Trapped charge is established in the second conductive layer. A first substrate for the second unit is provided. The second insulating layer is bonded to the first substrate for the second unit with electrostatic forces between the trapped charge and induced charge in the first substrate of the second unit.
A system for electrostatic bonding in accordance with another embodiment of the present invention includes a first substrate, a first conductive layer, a first insulating layer, a second conductive layer, a second insulating layer, and a second substrate. The first conductive layer is on at least a portion of the first substrate. The first insulating layer is on at least a portion of the first conductive layer. The second conductive layer is on at least a portion of the first insulating layer and has trapped charge. The second insulating layer is on at least a portion of the second conductive layer. The second substrate has induced charge and is bonded to the second insulating layer with electrostatic forces between the trapped charge and induced charge in the second substrate.
The present invention provides an easy and effective method and system for temporarily or permanently bonding or holding two units together, such as a component or sub-component on an assembly, by taking advantage of the extremely strong electrostatic attraction between fixed charge and reflected induced charge. The two units could also have opposite sign charge to create an even stronger attractive or bonding force.